The false statement is: (a) Transcriptional regulators usually interact with the sugar–phosphate backbone on the outside of the double helix to determine which DNA sequence to bind.
Transcriptional regulator or factor is protein with the ability to control and regulate gene expression at the transcription level by binding to DNA. Transcriptional factors have domain-DNA-binding domain which contains structural motif that recognizes DNA and it is responsible for the attachment to specific DNA sequence. It usually binds to the DNA major groove (hydrogen bonding) because it is less degenerate than that of the DNA minor groove.
Transcriptional factors also contain trans-activating domain for the binding of other proteins and signal-sensing domain for the detection of external signals.
Because the three-horned alien is heterozygous, we know that three must be dominant to four, because the gene for the three horns is "hiding" the gene for four horns. Therefore, the three-horned alien has the genotype Tt (T for three horns, and t for four horns). The four horned alien must be tt, because that is the only way that a recessive trait may be seen. If you solve the punnet square on a cross between Tt and tt, you end up with half three (heterozygous) and half four (homozygous recessive) it is a bit easier to explain with something a little "closer to home" if you want me to explain it again, just say so, I don't mind!
Answer:
Abiotic components of an ecosystem are water, air, light, soil, and temperature.
Now think about how the availability of these things will affect what could live in a specific area.
Consider a desert ecosystem. Deserts are arid, receiving little rain (water) and have extreme temperatures (both cold and hot). Because of these conditions only certain plants and animals can live here. These plants and animals have adaptations that are specific to the environment. If you were to put an organism that does not belong in there, they would most likely die out.
Tidbit for you. The Atacama desert is one of the driest places in the world, located specifically in Chile. At one point, this place did not receive any rain for 500 years! Still plants and animals are able to live in this area. When it finally did rain, the sudden downpour caused a radical change in this ecosystem. You would think at first rain would be good, but no. Because the changes the rain brought was too drastic, it caused a devastating effect on the organisms that lived there because they were not adapted to rain.
